Find the area of triangle BCD, in square centimeters.

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Explanation:
Use the area of a trapezoid formula, along with the given area, to solve for the height of the trapezoid (h)
A = h*(b1+b2)/2
741 = h*(23+34)/2
741 = h*28.5
741/28.5 = h
26 = h
h = 26
The height of the trapezoid is 26 cm
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Now we can find the area of triangle BCD. Its height is also 26 cm.
area of triangle = (1/2)*base*height
area of triangle BCD = (1/2)*BC*h
area of triangle BCD = (1/2)*34*26
area of triangle BCD = 442